Fuel efficient vehicles are desirable for cost savings and environmental benefits. Smaller engines tend to be more fuel efficient, but may be more limited in torque and power output. Performance flexibility can be realized by equipping an engine with continuously variable cylinder valves. Alternatively, a relatively large engine with a relatively high maximum torque can be used, with some cylinders selectively deactivated when torque demands are relatively low. However, uneven torque pulses may result when some of the cylinders are deactivated or the torque pulses at higher loads may generate undesirable noise, vibration and harshness (NVH) issues due to higher torque peaks at wider intervals. These issues may inhibit the useable dynamic range of the deactivated cylinders and reduce fuel economy. Furthermore, engines typically have predetermined optimal operating parameters at which combustion is most efficient.